According to a study published in the New England Medical Journal, universal facial masking helps in reducing the severity of SARS-CoV-2 and ensure that a greater proportion of new infections are asymptomatic.
Researchers hypothesised that universal masking could become a form of “variolation” that would generate immunity and thereby slow the spread of the virus.
Researchers wrote: “Universal facial masking seemed to be a possible way to prevent transmission from asymptomatic infected people.”
They mentioned in their study the recent data from Boston that showed a decrease in SARS-CoV-2 infections among health care workers after universal masking was implemented in municipal hospitals in late March.
Recent virologic, epidemiologic, and ecologic data have led to the hypothesis that facial masking may also reduce the severity of disease among people who do become infected, the authors of the study added.
They further hypothesised that wearing facial masks would reduce the viral inoculum to which the wearer is exposed and the subsequent clinical impact of the disease.
Since masks can filter out some virus-containing droplets, masking might reduce the inoculum that an exposed person inhales.
If this theory bears out, population-wide masking, with any type of mask that increases acceptability and adherence, might contribute to increasing the proportion of SARS-CoV-2 infections that are asymptomatic, the researchers added.
According to the authors, the typical rate of asymptomatic infection with coronavirus was estimated to be 40 per cent by the CDC in mid-July. However, asymptomatic infection rates are reported to be higher than 80 per cent in settings with universal facial masking.
Countries that have adopted population-wide masking have fared better in terms of rates of severe Covid-related illnesses and death. The countries also witnessed a shift from symptomatic to asymptomatic infections.
The researchers stated that most vaccine trials include a secondary outcome of decreasing the severity of illness since increasing the proportion of cases in which disease is mild or asymptomatic would be a public health victory.
Researchers mentioned: “Universal masking seems to reduce the rate of new infections; we hypothesise that by reducing the viral inoculum, it would also increase the proportion of infected people who remain asymptomatic.”